1. Field of the Invention
The system in question can be validly employed in the field of refrigerated and non-refrigerated counters used for the retail sale of food products such as meats, cheeses, pastries, etc.
2. Description of the Prior Art
The glass doors, both single and glass panel, of counters and display units for the sale of food products are variously attached to frames sustained by posts in order to insulate the food products contained from the external environment, protecting them against dust and/or insects.
Whereas the glass doors placed on the vendor side are small and easy to handle, the doors on the customer side are often very large and consequently heavy. The special shape some of the latter take on for aesthetic reasons further increase their dimensions and weight.
Unfortunately, the glass doors placed on the customer side need to be moved at least twice a day in order to clean the inside of the counter or unit and to insert or remove the foods contained.
A number of known systems can be used to move said glass doors. The simplest consists of removing the glass from its frame and placing it on the floor until the completion of the above mentioned daily operations. However, given the weight of the glass, this procedure is rather tiring and, furthermore, each time a serious risk of the glass sliding and breaking is run.
Other solutions entail the hinging of the top or bottom edge of each glass plate to facilitate movement ensuring that at least one side remains firmly attached to the frame, entailing less physical effort. Yet, even this solution is unable to solve all the problems operators have to face. If the glass is opened downwards, large glass plates must be sustained manually during the cleaning operations and insertion/removal of food products to prevent the hinges from breaking. Therefore, the problems are multiplied: on the one hand the operator has to make the effort of propping up the glass, on the other there is the problem of not being able to move along the counter or display unit as most of it is taken up by the open glass plate.
The opening of large glass doors towards the top is rather dangerous as the edges of the doors are at the same height as that of the head of the operator and the likely consequences are quite obvious. Further, the operator is forced to work by bending over and therefore in an uncomfortable position.
To reduce the physical strain on operators, glass doors can be servo controlled for shifting. Special gas pistons or springs lodged in the casing of the frame accompany the movement of the glass doors generally in upward direction.
Though this is a useful and valid technique, the danger of accidents to the operator's head still persists and the person is forced to work in a bent position. Another problem is the cost of this device. The use of pistons and/or springs for the lifting of the glass greatly increases the production cost of counters and display units and requires periodic maintenance, the cost of which is to be borne by the management.
Sliding glass doors are widely employed in this sector. The glass plates move longitudinally and therefore there is no strain on operators and they are not endangered in any way. Unfortunately, each glass plate used runs along its own slideway with the result that the edges of the different plates are superimposed and therefore never meet, and the dreaded insects or dust can gather in the gap between the plates.